1. Field of the Invention
The present invention relates to a vehicle control apparatus applied to vehicles which are provided, in a power transmission path between the engine and the drive wheels, with an automatic transmission which is operated by oil pressure from an oil pressure generation apparatus.
This application is based on Japanese Patent Application No. Hei 11-240585, the contents of which are incorporated herein by reference.
2. Description of the Related Art
As is commonly known, engine temporary stop systems, which temporarily stop the engine in the state in which the vehicle is stopped at a signal or the like, or when accelerator OFF has been continued for a fixed period of time, have come into practical application. By means of these engine temporary stop systems, the engine is driven only when necessary for running, and is stopped at other times, and thereby, it is possible to improve fuel consumption, and to reduce the amount of exhaust gases by shortening the period of engine drive.
Hybrid vehicles, which are operated using a separate engine and electric motor in accordance with the running conditions, are known as examples of vehicles which employ such engine temporary stop systems. In such hybrid vehicles, when the vehicle is stopped, the internal combustion engine is automatically stopped by a directive from a control apparatus, and when the vehicle is started, running is initiated using the electric motor as the source of drive power, and it is possible to restart the internal combustion engine using the electric motor as a starter.
By means of this, it is possible to greatly improve fuel consumption in cases in which the period of stop is relatively long, such as running during traffic jams and like. Furthermore, in hybrid vehicles, the structure was fundamentally one in which an electric motor was simply inserted between the internal combustion engine and the gear box in conventional vehicles (vehicles which are not hybrid vehicles), so that it was possible to use the internal combustion engines and gear boxes which were employed in conventionally mass produced vehicles in an unchanged manner, and it was possible to carry out manufacturing without providing special manufacturing facilities, and thus it was possible to restrict the increase in costs.
In such a hybrid vehicle, when the vehicle is caused to restart after a temporary period of engine stop, when the power source for vehicle running and the oil pump which serves to supply oil for lubrication and cooling to the gear box are simultaneously started, as a result of a delay in oil supply, insufficient engaging force of the friction engaging apparatus and the like used for shifting gears may cause a slip, or sufficient lubrication may not be obtained. That is to say, until the oil pump reaches a predetermined oil pressure at which oil can be supplied, there is a slight time delay, whereas, for example, in the case in which the vehicle is caused to start by using the electric motor as the source of drive force, a superior response can be obtained in comparison with the engine, and it is likely that a delay in the supply of oil will occur.
In order to deal with this problem, a technology has been proposed in which, by means of electrifying the oil pump and stipulating the start timing there, the oil pressure is caused to rise prior to the transmission of power from the power source to the transmission (for example, in Japanese Patent Application, Unexamined, No Hei 9-286245). However, in this technology, the oil pressure rise timing may only be set by the conditions of the vehicle itself, such as the start switch operating key position, and thus it is impossible to conduct supply of oil pressure which is appropriate to the road conditions, and it is difficult to appropriately exhibit the drive force required by the road conditions.
In light of these conditions, in the present invention, the object is to obtain sufficient drive force at an appropriate timing by correctly supplying oil pressure in accordance with road conditions, and thereby, to improve the driving operability.
The following structures were adopted in the present invention in order to achieve the object described above.
In a first aspect of the present invention, a vehicle control apparatus (for example, control apparatus 2 in the embodiment) for application to vehicles (for example, hybrid vehicle 1 in the embodiment) which is provided with, in a power transmission path between an engine (for example, engine E in the embodiment) and drive wheels (for example, drive wheels W in the embodiment), an automatic transmission (for example, CVT 6 in the embodiment) which operates by oil pressure from an oil pressure generation apparatus (for example, oil pump 4 in the embodiment), comprising: an engine stop permission determining device (for example, the processing of step S3 in the embodiment) for determining permission to stop the engine; a start need determining device (for example, the processing of step S4 in the embodiment) for determining the need for the start of the vehicle in accordance with data related to the road, when stop permission of the engine is given by the engine stop permission determining device; and an oil pressure maintaining device (for example, the processing of steps S5 and S6 in the embodiment) for maintaining operation of the oil pressure generation apparatus when it has been determined by the start need determining device that the start is required.
According to this vehicle control apparatus, a determination as to the engine stop permission is conducted by an engine stop permission determining device and a determination as to the necessity of start is carried out in the start need determining device, and furthermore, the operation of the oil pressure generation apparatus is maintained in the oil pressure maintaining device based on the determination of the necessity of start.
In this way, even when engine stop has been permitted, it is possible to maintain a state in which oil pressure is supplied to the automatic transmission where necessary, and by means of this, it is possible to immediately transmit drive force to the drive wheels in response to a start request from the driver. For this reason, it is possible to improve the driving operability.
In a second aspect of the present invention, the start need determining device is provided with a right or left turning operation detecting device (for example, the processing of step S42 in the embodiment) for detecting whether the vehicle is in a right or left turning operation, and determines that the start is required when it is detected that the vehicle is in a right or left turning operation.
By providing such a structure, when it has been detected that the vehicle is in a right or left turn operation, since it is recognized that start is required, even when the vehicle is in a right or left turning operation in an intersection or the like, it is possible to maintain a state of oil pressure supplied to the automatic transmission, and it is possible to immediately transmit drive force from the engine to the drive wheels in response to a start request from the driver during right or left turn operations. By means of this, it is possible to improve the driving operability.
In a third aspect of the present invention, when the right or left turning operation detecting device detects that the vehicle is in the vicinity of a right or left turning point, during route guidance of a navigation apparatus (for example, navigation apparatus 27 in the embodiment) installed in the vehicle, it is determined that the vehicle is in a right or left turning operation.
By providing such a structure, it is recognized that the vehicle is in a right or left turn operation when the vehicle is in the vicinity of a right or left turning point during route guidance by the navigation apparatus, so that using data which have been previously widely employed by conventional navigation apparatuses, it is possible to easily and reliably ascertain whether the vehicle is in a right or left turn operation using a simple structure without providing special apparatus. Accordingly, this is capable of broad applicability, and may even be satisfactorily applied to mass produced vehicles of the conventional type, so that it is possible to avoid increases in vehicle cost accompanying the introduction of new parts.
Furthermore, in a fourth aspect of the present invention, the right or left turning operation detecting device determines that the vehicle is in a right or left turning operation when it is detected that the vehicle is in a dedicated right or left turning lane, based on data relating to the road obtained from a navigation apparatus (for example, navigation apparatus 27 in the embodiment) installed in the vehicle.
By providing such a structure, when it has been detected that the vehicle is in a right or left turn lane by the navigation apparatus, it is determined that the vehicle is in a right or left turn operation, so that it is possible to easily and reliably ascertain whether the vehicle is in a right or left turn operation using a simple structure without providing special apparatus.
In a fifth aspect of the present invention, the start need determining device is provided with an upward slope detecting device (for example, the processing of step S43 in the embodiment) for detecting that a road surface on which the vehicle is positioned slopes upwardly in the direction of progress, and when an upward slope is detected, it is determined that the starting is required.
By providing this structure, it is determined that start is required when the vehicle is on a road surface which slopes upwardly in direction of progress, so that when start is conducted on a sloping road, the state of oil pressure supplied to the automatic transmission is maintained. That is to say, it is possible to constantly supply oil pressure to the automatic transmission when the vehicle is positioned on a road having an upward slope. For this reason, when start is conducted on a sloping road, it is possible to cause the immediate transmission of drive force from the engine to the drive wheels in response to a start request from the driver. By means of this, it is possible to improve the driving operability.
In a sixth aspect of the present invention, the upward slope-detecting device determines whether the vehicle is positioned at a forward rise in the direction of progress based on the detection results of a vehicle forward and reverse acceleration sensor (for example, the G sensor 28 in the embodiment) positioned in the vehicle, and if a determination of forward rise is made, conducts detection of the upward slope.
By providing this structure, a determination is conducted as to whether the vehicle is on an upward sloping road surface based on the detection results of the vehicle forward and reverse direction acceleration sensor, so that it is possible to easily and reliably confirm whether the vehicle is on an upwardly sloping road surface using a simple structure without requiring special apparatus. Accordingly, this is capable of broad application, and it is possible to satisfactorily apply this to mass produced vehicles of the conventional type, so that it is possible to avoid increases in vehicle cost accompanying introduction of new parts.
Furthermore, in a seventh aspect of the present invention, the upward slope detecting device determines whether the height above sea level of the vehicle in the direction of progress is increasing based on data relating to the road obtained from a navigation apparatus (for example, navigation apparatus 27 in the embodiment) installed in the vehicle, and when it is determined that the height above sea level is increasing, conducts detection of the upward slope.
By providing this structure, it is recognized that the vehicle is on an upward slope when a determination is made that the height above sea level increases in the direction of progress of the vehicle, using data relating to the road obtained from the navigation apparatus, so that it is possible to easily and reliably ascertain whether the vehicle is on an upward sloping road surface using a simple structure without requiring special apparatus.
In a eighth aspect of the present invention, the oil pressure generation apparatus is comprised so as to be driven by the engine, and the oil pressure maintaining device is comprised so as to maintain operation of the oil pressure generation apparatus by canceling the stop permission of the engine.
Since this type of structure is provided, the operation of the engine is continued in order to maintain the supply of oil pressure, and in contrast to the conventional art, there is no need to control the startup timing of the oil pump using an electric motor or the like, so that it is not necessary to add additional parts, such as a motor-driven pump or the like, to maintain the oil pressure. By means of this, it is possible to avoid increased vehicle costs accompanying the introduction of new parts.